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Gieseler Audio

Raspberry Pi Klein combo interest

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Sounds like a great idea.

But what are the disadvantages of having the Pi in the DAC?

I use my cd player as a transport via spdif (rca) to my dac, so loss of spdif is one disadvantage for me.

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Somebody mentioned a modular design previously in this or another thread. Could you offer a modular design dac, Pi, pre?

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Looks like sd card reader slot will have to be at the top or side

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Oh, and the Beaglebone Black is supported by RuneAudio so I'm a happy-chappy. No love from OpenELEC for the Beaglebone Black (not supported). "Doesn't madda!" (Con the Fruiterer) Music is more important. I can always use my Pi for movies and the Klein-II-Pi (Klein-2-Pi, Klein-Pi) for music. "Bewdiful!" (Con the Fruiterer)

Edited by rastus

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Clay, I thought the intention would be to make a standalone player.... If so you wouldn't need access to the sd card. Once setup with the player software its done. Also note i have the official 7" touch screen on mine and its works a treat with Rune, first software I've tried.

Sent from my D5833 using Tapatalk

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Well this would be a "standalone player".... with the option (if the buyer so chose) to alter the software (usually done on a PC with a card reader because PuTTy and the Archlinux command line is just a bit too complex for configuration and updating)... and as RuneAudio and most of these software's don't have an internal 'button' to update (although the next incarnation of RuneAudio should have this feature, and there may also be other OS's that do, piCoreplayer, Max2play, etc)... and, what about SD card failure replacement (return to base?), and it does happen with the Pi... another option (that becomes very complex) is adding an SSD drive (price increase alert) to run the OS... the option to add a "7" touch screen" is not really needed if the Pi can be accessed via a web browser, but a nice idea (price increase alert), I do like it though.

 

Can I have mine painted with the Batman symbol on the topmost face of the case? Then I could stick the SD card into Batman's mouth! Ruuuuly cool! But seriously, I like this idea.

 

PS: Not the Batman thing, was joshing about that. Sorry, I'll stop posting... honest.

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Wow guys (where are the girls?) I had no idea there would be such a massive response.

Rastus thanks for your wealth of information & no you have not overdone it - keep it coming.

I think Greigw asked what was the advantage of having the Pi inside the DAC or disadvantage of it being on the outside.

The main reason for having it in the DAC is to get the maximum sound quality we can out of the little Raspberry Pi. To do this with the least amount circuitry & processing we need to directly take the I2S data from the Pi & feed it straight into the AK4490 DAC chip. It is best to keep the I2S lines as short as possible & without plugs, sockets,relays ect. The best way to implement that is have the Pi directly plug into the motherboard close to the DAC chip & that's what I plan to do. The other advantage is I will have a dedicated low noise PSU on the motherboard right next to the Pi to feed it top notch power.

Implementing the above two options should give us a very high quality audio possibly even better than the previous USB input.

Fingers crossed!

As the Pi has no MCK out I will have to add reclocking & may even add galvanic isolation on the I2S lines while I'm at it.

The whole concept is to keep the unit fairly basic but with top quality audio. Ethernet in - RCA audio out - balanced could be an option too.

Edited by Gieseler Audio

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OOOooooh! :thumb:

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If the Klein DAC 2 can do DSD, why can't this one do it?

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The idea is awesome, it's been floating in my head for a few weeks now too.

 

Complications I saw (for me) on the way, the driver(s) installed on RuneAudio (or the OSS of your choice) may or may not be compatible with the I2S DAC. As far as I know, all (most) official distributions have the HIFIBerry Dac+ drivers. They include the PCM interface (Clk Slave / FS / Data) plus the control interface (volume, sampling frequency, etc, etc). If you wanted to use your own DAC, you might have to rewrite the drivers (I'm still struggling with that).

 

Would the Klein v3.14159 still have coax and optical input? That's another thing that's putting me a bit off with DIYing that solution, I'd still want all three (PC/Coax/Optical) interfaces, seeing how I use them all.

 

I like the idea, but user-friendliness should be granted for all the not-tech-savvy folk.

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Betocool - yes there are probably going to be plenty of issues sorting I2S DAC compatibility out for sure.

After a bit of researching tonight it looks like trying to extract DSD via the I2S port on the Pi is a no go too.

Anyway the main thing was to check general interest in the project & it appears there certainly is.

OK, I have a spare Pi 2B & standard Klein motherboard so I will actually build up a working prototype & then do some serious testing - hardware & software. Also I was thinking of dropping the optical/coax inputs but it might be good to get a vote on that later.

Thanks everyone for all the feedback & input.

Once I have a working unit & performed some testing I will post an update & some photos.

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Rastus thanks for your wealth of information & no you have not overdone it - keep it coming.

As the Pi has no MCK out I will have to add reclocking & may even add galvanic isolation on the I2S lines while I'm at it.

 

The whole concept is to keep the unit fairly basic but with top quality audio. Ethernet in - RCA audio out - balanced could be an option too.

 

OK. Nice. And nicer. Indeed, indeed.

 

The idea is awesome, it's been floating in my head for a few weeks now too.

 

If you wanted to use your own DAC, you might have to rewrite the drivers (I'm still struggling with that).

 

I like the idea, but user-friendliness should be granted for all the not-tech-savvy folk.

 

Indeed... awe-SOME! I may be... able to... get this... done, maybe (I sure would move hell and high water to try). I agree with this, wholeheartedly... but I think the option should be there in case a tech savvy folk wanted to.. do what a tech savvy folk does (without infringing upon a not-so-tech-savvy folk of course).... sort of please all the people all the time. Anyway, thus the need for access to the mini SD card.

 

Betocool - yes there are probably going to be plenty of issues sorting I2S DAC compatibility out for sure.

After a bit of researching tonight it looks like trying to extract DSD via the I2S port on the Pi is a no go too.

 

Anyway the main thing was to check general interest in the project & it appears there certainly is.

OK, I have a spare Pi 2B & standard Klein motherboard so I will actually build up a working prototype & then do some serious testing - hardware & software. Also I was thinking of dropping the optical/coax inputs but it might be good to get a vote on that later.

Once I have a working unit & performed some testing I will post an update & some photos.

 

Plenty maybe, but insurmountable? No? I hope not, for not's sake. No go? Does that mean no go? Not a goer? As in, no go what-so-ever-go? Is that because of the hardware side of things? Because surely the software can be adapted....

 

"FFmpeg decoder plugin"

"DSD Support enables and disables support for playing DSD Audio."

http://www.runeaudio.com/documentation/runeui/mpd/

"Bitperfect and gapless playback of common audio formats and support of native DSD playback with DSD-over-PCM."

http://www.runeaudio.com/

 

Maybe I'm off the mark on this, I'm no good with circuitry stuff... really bad, bad, bad. Anyway, 'general' interest you got.... and here I was going to post over in the "Digital, DACs & Computer Audio" section and mention this thread to garner up some more interest (support). I really don't think 'they' are all watching the "Gieseler Audio" section for their Digital, DAC and Computer Audio information (or developments like this). OK, so grim it seems... and yet promising all at the same time. A vote, yes. Working unit, testing, update and photos... OK, gotcha. So... I'll wait here OK. Already wrestled the woman to the ground, pinched her purse, took out $900 (just in case you go all 'tough' on me and want to haggle some).

 

PS: But seriously Clayton (and I do mean this), thank you very much for even considering this as a possibility. It is a great idea, and it has great potential, and it was great to give you some input/feedback (after all the input/feedback you know you have given me). Tah.

 

PSS: I could get a lot more interested parties over here to post, in the twinkle of an eye. :popcorn:

 

PSSS: From the RuneAudio forum...

"...the new image for RP2/3 can play native DSD to USB DACs. For this to work the MPD configuration has to be tweaked by hand. This will change soon with the next image. Native DSD does not work with all DACs see https://github.com/lintweaker/xmos-native-dsd"

Linux native DSD playback support

https://github.com/lintweaker/xmos-native-dsd

Edited by rastus

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Rastus - I really appreciate your support & enthusiasm for this - thanks.

Yes put that $900 in a coffee tin,stash it somewhere safe & away from the wife.

DSD via Pi's I2S ports, please do your own research but but from from what I found & only from about thirty minutes of on line looking seems to suggest it wasn't possible. Of course this could change at any moment especially with the massive Pi resource base. I'm definitely a hardware man with limited Linux skills so not much help in that area. DSD via USB + Pi is certainly do-able, it's the I2S side where the problem is. I think the Pink Faun I2S Bridge will not extract DSD either so there is obviously something tricky required on the software side. Chanh & Tasso have done a lot with the Arm core boards as streamers so maybe we should bounce it off them. The Beaglebone Black seems stronger in the I2S area so I might do some more R&D on that.

Anyway I'm very keen to get this happening so as soon as I have a live hardware model working I will do heaps of testing.

Edited by Gieseler Audio

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Clay, forgive me if somewhere I've missed you addressing this but if I were you I'd first be checking out the existing rpi i2s dac addon boards (like hifiberry dac+ pro). You need to very sure sure your dac once you work out the i2s difficulties will clearly outperform these readily available pi i2s boards (sub $100us). By incorporating a Pi in your product, you are also taking ownership of the software and user interface issues -- a not trivial task that does not seem well suited to your existing core skills. Given the very rapid development going on in this area perhaps you could consider focusing on best exploiting your core skills. For example, you could readily distinguish your DAC from the competition using your great power supply engineering skill by designing for (optionally) a 1 or 2 additional configurable power supply outlets user configurable for 5v, 7.5v, 9v up to 2.5 amps and now you've got a dac with built in audiophile quality power supply(ies) on tap for the user's renderer of choice, be it a pi, BBB, Odroid, Sonicorbiter/cubox, microRendu or a zillion other upstream options that are here and going to appear in the digital transport/endpoint space. Absolutely not wanting to rain on the parade because making this all easier for folks to get started with audiophile quality digital music is laudable. Just food for thought anyway because I think the one thing established in this volatile space is that quality power supply makes a massive difference be it i2s or usb sources. At least get chummy with someone with the all the computer/OS skills if you want to incorporate a renderer into your dac. Hope this helps & best of luck with your R&D Clay. Cheers, essem.

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